;function: delete all entities outside closed polylines.
;required "extrim.lsp" from express tools
;the lisp is modification from "Erases Everything OutSide Contour Delete with Extrim"
;published on : http://forums.augi.com/showthread.php?55056-Erasing-everything-outside-a-boundary
;modified by: zainul_ulum@cbn.net.id
;modification-01: 30 March 2018
;additonal requirement: closed polylines as boundary for clipping/trimming are located on layer "z_clip"

(defun c:zdob ( / *error* o_cmdecho o_osmode clip_layer aDoc ff filter ss nn kk en)

  (defun *error* (msg);;error handling
    (princ msg);display error message
    (setvar "cmdecho" o_cmdecho);restore to prev cmdecho
    (setvar "osmode" o_osmode);restore to old prev mode
    ;end undo marking
    (vla-EndUndoMark aDoc)
      );end error handling

 
  (vl-load-com);load autolisp com
  (setq o_cmdecho (getvar "cmdecho"));get current cmdecho variable
  (setq o_osmode (getvar "osmode"));get current osnap variable
  (setq clip_layer "z_clip");layer where boudary polylines are located
  (setq aDoc (vla-get-activedocument (vlax-get-acad-object)));get activedocument / active document

  ;setting new system variables prior to process trimming
  (setvar "cmdecho" 0)
  (setvar "osmode" 0)

  ;starting undo Marking
  (vla-StartUndoMark aDoc)

  ;select one polyline boundaries on layer z_clip
  (setq filter (cons 8 clip_layer))
  (setq ss (ssget ":S" (list filter)))
  (setq en (ssname ss 0)); select only one entity
    (if
          (wcmatch (cdr (assoc 0 (entget en))) "*POLYLINE")
    (progn
      ;start trimming
      (delete_outside_boundary en)
      ;save trimmed drawing
      ;start
      );end progn "*POLYLINE"
    );end if
       
;restore prev variables and end undo marking
    (setvar "cmdecho" o_cmdecho);restore to prev cmdecho
    (setvar "osmode" o_osmode);restore to old prev mode
    (vla-EndUndoMark (vla-EndUndoMark aDoc))
);end obd
(princ "\nType zdob")
(defun delete_outside_boundary (en)
  ;some functions are referred to extrim.lsp
  (setq bbox (ACET-ENT-GEOMEXTENTS en))
  (setq bbox (mapcar ‘(lambda (x) (trans x 0 1)) bbox))
  (setq lst (ACET-GEOM-OBJECT-POINT-LIST en 1e-3))
  (ACET-SS-ZOOM-EXTENTS (ACET-LIST-TO-SS (list en)))
  (command "_.Zoom" "0.95x")
  (if (null etrim)
    (load "extrim.lsp")
    );end if

  (etrim en
     (polar
       (car bbox)
       (angle (car bbox) (cadr bbox))
       (* (distance (car bbox) (cadr bbox)) 1.1))
     );end etrim
  (if (and (setq ss (ssget "_CP" lst))
       (setq ssall (ssget "_X" (list (assoc 410 (entget en)))))
       );and
    (progn
      (setq lst (vl-remove-if ‘listp (mapcar ‘cadr (ssnamex ss))))
      (foreach e1 lst (ssdel e1 ssall))
      (ACET-SS-ENTDEL ssall)
      );end progn
    );end if
    ;(command "_erase" en "")
);end delete outside boundary